Contact structure and production method thereof and probe contact assembly using same

ABSTRACT

A contact structure for establishing electrical connection with contact targets. The contact structure is formed of a contact substrate and a plurality of contactors. The contactor has a contact portion which is protruded in a vertical direction to form a contact point, an intermediate portion which is inserted in a through hole provided on the contact substrate, and a base portion having a base end which functions as a contact pad and a spring portion provided between the base end and the intermediate portion for producing a resilient contact force when the contactor is pressed against the contact target.

[0001] This is a continuation-in-part of U.S. patent application Ser.No. 09/201,299 filed Nov. 30, 1998 and U.S. patent application Ser. No.09/503,903 filed Feb. 14, 2000.

FIELD OF THE INVENTION

[0002] This invention relates to a contact structure and a productionmethod thereof and a probe contact assembly using the contact structure,and more particularly, to a contact structure having a large number ofcontactors in a vertical direction and to a method for producing such alarge number of contactors on a semiconductor wafer in a horizonaldirection and removing the contactors from the wafer to be mounted on asubstrate in a vertical direction to form the contact structure such asa contact probe assembly, probe card, IC chip, or other contactmechanism.

BACKGROUND OF THE INVENTION

[0003] In testing high density and high speed electrical devices such asLSI and VLSI circuits, a high performance contact structure such as aprobe card having a large number of contactors must be used. In otherapplications, contact structures may be used for IC packages as ICleads. The present invention is directed to a production process of suchcontact structures to be used in testing LSI and VLSI chips,semiconductor wafers, burn-in of semiconductor wafers and die, testingand burn-in of packaged semiconductor devices, printed circuit boardsand the like. The present invention can also be applicable to otherpurposes such as forming leads or terminal pins of IC chips, IC packagesor other electronic devices. However, for the convenience ofexplanation, the present invention is described mainly with reference tothe semiconductor wafer testing.

[0004] In the case where semiconductor devices to be tested are in theform of a semiconductor wafer, a semiconductor test system such as an ICtester is usually connected to a substrate handler, such as an automaticwafer prober, to automatically test the semiconductor wafer. Such anexample is shown in FIG. 1 in which a semiconductor test system has atest head 100 which is ordinarily in a separate housing and electricallyconnected to the test system with a bundle of cables 110. The test head100 and a substrate handler 400 are mechanically as well as electricallyconnected with one another with the aid of a manipulator 500 which isdriven by a motor 510. The semiconductor wafers to be tested areautomatically provided to a test position of the test head 100 by thesubstrate handler 400.

[0005] On the test head 100, the semiconductor wafer to be tested isprovided with test signals generated by the semiconductor test system.The resultant output signals from the semiconductor wafer under test (ICcircuits formed on the semiconductor wafer) are transmitted to thesemiconductor test system. In the semiconductor test system, the outputsignals are compared with expected data to determine whether the ICcircuits on the semiconductor wafer function correctly.

[0006] In FIG. 1, the test head 100 and the substrate handler 400 areconnected through an interface component 140 consisting of a performanceboard 120 (shown in FIG. 2) which is a printed circuit board havingelectric circuit connections unique to a test head's electricalfootprint, coaxial cables, pogo-pins and connectors. In FIG. 2, the testhead 100 includes a large number of printed circuit boards 150 whichcorrespond to the number of test channels (test pins) of thesemiconductor test system. Each of the printed circuit boards 150 has aconnector 160 to receive a corresponding contact terminal 121 of theperformance board 120. A “frog” ring 130 is mounted on the performanceboard 120 to accurately determine the contact position relative to thesubstrate handler 400. The frog ring 130 has a large number of contactpins 141, such as ZIF connectors or pogo-pins, connected to contactterminals 121, through coaxial cables 124.

[0007] As shown in FIG. 2, the test head 100 is placed over thesubstrate handler 400 and mechanically and electrically connected to thesubstrate handler through the interface component 140. In the substratehandler 400, a semiconductor wafer 300 to be tested is mounted on achuck 180. In this example, a probe card 170 is provided above thesemiconductor wafer 300 to be tested. The probe card 170 has a largenumber of probe contactors (such as cantilevers or needles) 190 tocontact with contact targets such as circuit terminals or contact padsin the IC circuit on the semiconductor wafer 300 under test.

[0008] Electrical terminals or contact receptacles (contact pads) of theprobe card 170 are electrically connected to the contact pins 141provided on the frog ring 130. The contact pins 141 are also connectedto the contact terminals 121 of the performance board 120 with thecoaxial cables 124 where each contact terminal 121 is connected to theprinted circuit board 150 of the test head 100. Further, the printedcircuit boards 150 are connected to the semiconductor test systemthrough the cable 110 having, for example, several hundreds of innercables.

[0009] Under this arrangement, the probe contactors 190 contact thesurface (contact target) of the semiconductor wafer 300 on the chuck 180to apply test signals to the semiconductor wafer 300 and receive theresultant output signals from the wafer 300. The resultant outputsignals from the semiconductor wafer 300 under test are compared withthe expected data generated by the semiconductor test system todetermine whether the IC circuits on the semiconductor wafer 300performs properly.

[0010]FIG. 3 is a bottom view of the probe card 170 of FIG. 2. In thisexample, the probe card 170 has an epoxy ring on which a plurality ofprobe contactors 190 called needles or cantilevers are mounted. When thechuck 180 mounting the semiconductor wafer 300 moves upward in FIG. 2,the tips of the cantilevers 190 contact the pads or bumps (contacttargets) on the wafer 300. The ends of the cantilevers 190 are connectedto wires 194 which are further connected to transmission lines (notshown) formed in the probe card 170. The transmission lines areconnected to a plurality of electrodes (contact pads) 197 which are incommunication with the pogo pins 141 of FIG. 2.

[0011] Typically, the probe card 170 is structured by a multilayer ofpolyimide substrates having ground planes, power planes, signaltransmission lines on many layers. As is well known in the art, each ofthe signal transmission lines is designed to have a characteristicimpedance such as 50 ohms by balancing the distributed parameters, i.e.,dielectric constant and magnetic permeability of the polyimide,inductances and capacitances of the signal paths within the probe card170. Thus, the signal lines are impedance matched lines establishing ahigh frequency transmission bandwidth to the wafer 300 for supplyingcurrents in a steady state as well as high current peaks generated bythe device's outputs switching in a transient state. For removing noise,capacitors 193 and 195 are provided on the probe card between the powerand ground planes.

[0012] An equivalent circuit of the probe card 170 is shown in FIG. 4 toexplain the limitation of the high frequency performance in theconventional probe card technology. As shown in FIGS. 4A and 4B, thesignal transmission line on the probe card 170 extends from theelectrode 197, the strip (impedance matched) line 196, the wire 194 andthe needle or cantilever (contact structure) 190. Since the wire 194 andneedle 190 are not impedance matched, these portions function as aninductor L in the high frequency band as shown in FIG. 4C. Because ofthe overall length of the wire 194 and needle 190 is around 20-30 mm,significant limitations will be resulted from the inductor when testinga high frequency performance of a device under test.

[0013] Other factors which limit the frequency bandwidth in the probecard 170 reside in the power and ground needles shown in FIGS. 4D and4E. If the power line can provide large enough currents to the deviceunder test, it will not seriously limit the operational bandwidth intesting the device. However, because the series connected wire 194 andneedle 190 for supplying the power (FIG. 4D) as well as the seriesconnected wire 194 and needle 190 for grounding the power and signals(FIG. 4E) are equivalent to inductors, the high speed current flow isseriously restricted.

[0014] Moreover, the capacitors 193 and 195 are provided between thepower line and the ground line to secure a proper performance of thedevice under test by filtering out the noise or surge pulses on thepower lines. The capacitors 193 have a relatively large value such as 10μF and can be disconnected from the power lines by switches ifnecessary. The capacitors 195 have a relatively small capacitance valuesuch as 0.01 μF and fixedly connected close to the DUT. These capacitorsserve the function as high frequency decoupling on the power lines. Inother words, the capacitors limit the high frequency performance of theprobe contactor.

[0015] Accordingly, the most widely used probe contactors as noted aboveare limited to the frequency bandwidth of approximately 200 MHz which isinsufficient to test recent semiconductor devices. In the industry, itis considered that the frequency bandwidth comparable to the tester'scapability, which is currently on the order of 1 GHz or higher, will benecessary in the near future. Further, it is desired in the industrythat a probe card is capable of handling a large number of semiconductordevices, especially memories, such as 32 or more, in a parallel fashionto increase test throughput.

[0016] In the conventional technology, the probe card and probecontactors such as shown in FIG. 3 are manually made, resulting ininconsistent quality. Such inconsistent quality includes fluctuations ofsize, frequency bandwidth, contact forces and resistance, etc. In theconventional probe contactors, another factor making the contactperformance unreliable is a temperature change under which the probecontactors and the semiconductor wafer under test have differenttemperature expansion ratios. Thus, under the varying temperature, thecontact positions therebetween vary which adversely affects the contactforce, contact resistance and bandwidth. Thus, there is a need of acontact structure with a new concept which can satisfy the requirementin the next generation semiconductor test technology.

SUMMARY OF THE INVENTION

[0017] Therefore, it is an object of the present invention to provide acontact structure having a large number of contactors for electricallycontacting contact targets with a high frequency bandwidth, high pincounts and high contact performance as well as high reliability.

[0018] It is another object of the present invention to provide acontact structure such as a probe card to establish electricalconnection for testing semiconductor devices and the like, having a veryhigh frequency bandwidth to meet the test requirements in the nextgeneration semiconductor test technology.

[0019] It is a further object of the present invention to provide acontact structure to establish electrical connection in applicationssuch as testing semiconductor devices, which are suitable for testing alarge number of semiconductor devices in parallel at the same time.

[0020] It is a further object of the present invention to provide acontact structure and its assembly mechanism for assembling a pluralityof contact structures to form a probe contact assembly of desired sizewith desired number of contactors mounted on the probe contact assembly.

[0021] It is a further object of the present invention to provide amethod for producing a large number of contactors in a two dimensionalmanner on a silicon substrate, removing the contactors from thesubstrate and mounting the contactors on a contact substrate in a threedimensional manner to form a contact structure.

[0022] It is a further object of the present invention to provide amethod for producing a large number of contactors in a two dimensionalmanner on a silicon substrate, transferring the contactors to anadhesive tape and removing the contactors therefrom for verticallymounting the same on a contact substrate to forma a contact structure.

[0023] In the present invention, a contact structure for testing(including burn-in) semiconductor wafers, packaged LSIs or printedcircuit boards (devices under test) are formed of a large number ofcontactors produced on a planar surface of a substrate such as a siliconsubstrate by a photolithography technology established in thesemiconductor production process. The contact structure of the presentinvention can also be used as components of electronics devices such asIC leads and pins.

[0024] The first aspect of the present invention is a contact structurefor establishing electrical connection with contact targets. The contactstructure is formed of a contact substrate and a plurality of contactorsin which each of the contactors has a substantially straight shape. Thecontactor is comprised of a contact portion which is protruded in avertical direction to form a contact point, an intermediate portionwhich is inserted in a through hole provided on the contact substrate,and a base portion having a base end which functions as a contact padand a spring portion provided between the base end and the intermediateportion for producing a resilient contact force when the contactor ispressed against the contact target.

[0025] Another aspect of the present invention is a method of producingthe contactors in a two dimensional manner on a silicon substrate andremoving therefrom for establishing a contact structure. The productionmethod is comprised of the following steps of:

[0026] (a) forming a sacrificial layer on a surface of a siliconsubstrate;

[0027] (b) forming a photoresist layer on the sacrificial layer;

[0028] (c) aligning a photo mask over the photoresist layer and exposingthe photoresist layer with ultraviolet light through the photo mask, thephoto mask including an image of the contactors each having a springportion between a base portion and an intermediate portion;

[0029] (d) developing patterns of the image of the contactors on asurface of the photoresist layer;

[0030] (e) forming the contactors made of conductive material in thepatterns on the photoresist layer by depositing the conductive material;

[0031] (f) stripping the photoresist layer off;

[0032] (g) removing the sacrificial layer by an etching process so thatthe contactors are separated from the silicon substrate; and

[0033] (h) mounting the contactors on a contact substrate having throughholes to receive ends of the contactors therein so that at least one endof each of the contactors functions as a contact pad for electricconnection.

[0034] A further aspect of the present invention is another method ofproducing the contactors in a two dimensional manner on a siliconsubstrate and transferring the contactors to the adhesive tape andremoving therefrom for establishing a contact structure. The productionmethod is comprised of the following steps of:

[0035] (a) forming a sacrificial layer on a surface of a substrate;

[0036] (b) forming a photoresist layer on the sacrificial layer on thesubstrate;

[0037] (c) aligning a photo mask over the photoresist layer and exposingthe photoresist layer with ultraviolet light through the photo mask, thephoto mask including an image of the contactors each having a springportion between a base portion and an intermediate portion;

[0038] (d) developing patterns of the image of the contactors on asurface of the photoresist layer;

[0039] (e) forming the a first layer of contactors made of electricconductive material in the patterns on the photoresist layer by anelectroplating process;

[0040] (f) stripping the photoresist layer off;

[0041] (g) placing an adhesive tape on the contactors so that uppersurfaces of the contactors are attached to the adhesive tape;

[0042] (h) removing the sacrificial layer by an etching process so thatthe contactors on the adhesive tape are separated from the siliconsubstrate; and

[0043] (i) mounting the contactors on a contact substrate having throughholes to receive therein ends of the contactors wherein at least one endof each of the contactors function as a pad for electric connection.

[0044] A further aspect of the present invention is a method ofproducing the contactors in a two dimensional manner on a siliconsubstrate and transferring the contactors to the adhesive tape. Theproduction method is comprised of the following steps of:

[0045] (a) forming an conductive substrate made of electric conductivematerial on a dielectric substrate;

[0046] (b) forming a photoresist layer on the conductive substrate;

[0047] (c) aligning a photo mask over the photoresist layer and exposingthe photoresist layer with ultraviolet light through the photo mask, thephoto mask including an image of the contactors each having a springportion between a base portion and an intermediate portion;

[0048] (d) developing patterns of the image of the contactors on asurface of the photoresist layer;

[0049] (e) forming a first layer of contactors made of electricconductive material in the patterns on the photoresist layer by anelectroplating process;

[0050] (f) stripping off the photoresist layer;

[0051] (g) placing an adhesive tape on the contactors on the conductivesubstrate so that upper surfaces of the contactors adhere to theadhesive tape wherein adhesive strength between the contactor and theadhesive tape is larger than that between the contactor and theconductive substrate;

[0052] (h) peeling the conductive substrate so that the contactors onthe adhesive tape are separated from the conductive substrate; and

[0053] (i) mounting the contactor on a contact substrate having athrough hole in such a way the an end of the contactor is projected froman opposite surface of the contact substrate.

[0054] A further aspect of the second present invention is a probecontact assembly including the contact structure of the presentinvention. The probe contact assembly is formed of a contact substratehaving a plurality of contactors mounted on a surface thereof, a probecard for mounting the contact substrate and establishing electricalcommunication between the contactors and electrodes provided on theprobe card, and a pin block having a plurality of contact pins tointerface between the probe card and a semiconductor test system whenthe pin block is attached to the probe card.

[0055] The contactors are mounted vertically on a horizontal surface ofthe contact surface where each of the contactors has a substantiallystraight shape. Each contactor is comprised of a tip portion which isprotruded in a vertical direction to form a contact point, anintermediate portion which is inserted in a through hole provided on thecontact substrate, and a base portion having a base end which functionsas a contact pad and a spring portion provided between the base end andthe intermediate portion for producing a resilient contact force whenthe contactor is pressed against the contact target.

[0056] According to the present invention, the contact structure has avery high frequency bandwidth to meet the test requirements of nextgeneration semiconductor technology. Since the large number ofcontactors are produced at the same time on the substrate withoutinvolving manual handling, it is possible to achieve consistent quality,high reliability and long life in the contact performance as well as lowcost. Further, because the contactors are assembled on the samesubstrate material as that of the device under test, it is possible tocompensate positional errors caused by temperature changes.

[0057] Further, according to the present invention, the productionprocess is able to produce a large number of contactors in a horizontaldirection on the silicon substrate by using relatively simple technique.Such contactors are removed from the substrate and mounted on a contactsubstrate in a vertical direction. The contact structure produced by thepresent invention are low cost and high efficiency and have highmechanical strength and reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0058]FIG. 1 is a schematic diagram showing a structural relationshipbetween a substrate handler and a semiconductor test system having atest head.

[0059]FIG. 2 is a diagram showing an example of more detailed structurefor connecting the test head of the semiconductor test system to thesubstrate handler through an interface component.

[0060]FIG. 3 is a bottom view showing an example of the probe cardhaving an epoxy ring for mounting a plurality of probe contactors(needles or cantilevers) in the conventional technology.

[0061] FIGS. 4A-4E are circuit diagrams showing equivalent circuits ofthe probe card of FIG. 3.

[0062]FIG. 5 is a schematic diagram showing an example of contactstructure of the present invention using contactors produced in ahorizontal direction on a substrate and vertically mounted on a contactsubstrate.

[0063]FIG. 6 is a schematic diagram showing another example of contactstructure of the present invention using contactors produced in ahorizontal direction on a substrate and vertically mounted on a contactsubstrate.

[0064]FIG. 7 is a schematic diagram showing a further example of contactstructure of the present invention using contactors produced in ahorizontal direction on a substrate and vertically mounted on a contactsubstrate.

[0065]FIGS. 8A and 8B are schematic diagrams showing basic concepts ofproduction method of the present invention in which a large number ofcontactors are formed on a planar surface of a substrate and removedtherefrom for later processes.

[0066] FIGS. 9A-9F are schematic diagrams showing examples of shape incontactors to be produced in the production process of the presentinvention and to be used in the contact structures of the presentinvention.

[0067]FIGS. 10A and 10B are diagrams showing a specific example ofcontactor of the present invention wherein FIG. 10A is a front view ofthe contactor and FIG. 10B is a side view of the contactor.

[0068] FIGS. 11A-11L are schematic diagrams showing an example ofproduction process in the present invention for producing thecontactors.

[0069] FIGS. 12A-12D are schematic diagrams showing another example ofproduction process in the present invention for producing thecontactors.

[0070] FIGS. 13A-13N are schematic diagrams showing an example ofprocess for producing contact structures in the horizontal surface of asubstrate and transferring the contactors to an intermediate plate.

[0071]FIGS. 14A and 14B are schematic diagrams showing an example ofpick and place mechanism and its process for picking the contactors andplacing the same on a substrate such as a multi-layered siliconsubstrate to produce the contact structure of the present invention.

[0072]FIG. 15 is a cross sectional view showing an example of probecontact assembly using the contact structure of the present invention asan interface between a semiconductor device under test and a test headof a semiconductor test system.

[0073]FIG. 16 is a cross sectional view showing another example of probecontact assembly using the contact structure of the present invention asan interface between a semiconductor device under test and a test headof a semiconductor test system.

[0074]FIG. 17 is a cross sectional view showing a further example ofprobe contact assembly using the contact structure of the presentinvention as an interface between a semiconductor device under test anda test head of a semiconductor test system.

[0075]FIG. 18 is a schematic diagram showing an example of contactstructure of the present invention having a multilayered standardsilicon substrates and the contactors produced through the productionprocess of the present invention.

[0076]FIG. 19 is a perspective view showing a plurality of contactstructures of the present invention each having a large number ofcontactors for assembling with one another to constitute a probe contactassembly of desired size.

[0077]FIG. 20 is a perspective view of the contact structure of thepresent invention wherein plural contact substrates are connected withone another to establish a probe contact assembly with desired size,shape and number of contactors.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0078] FIGS. 5-7 show examples of contact structure of the presentinvention. Each contact structure is configured by a contact substrate20 and contactors 30. In the example of FIG. 5, each contactor 30 ₁extends substantially in a vertical direction and is formed of anintermediate portion which is connected to the contact substrate 20, acontact portion which is preferably sharpened at the lower end of FIG.5, and a first spring portion between the intermediate portion and thecontact portion to function as a contact spring, a base portion having acontact point at the top end and a second spring portion between thebase portion and the intermediate portion to function as a contactspring.

[0079] In the example of FIG. 6, each contactor 30 ₂ extendssubstantially in the vertical direction and is formed of an intermediateportion which is connected to the contact substrate 20, a contactportion having straight shape with a tip end which is preferablysharpened at the lower end of FIG. 5, and a base portion having acontact point at the top end and a spring portion between the baseportion and the intermediate portion.

[0080] In the example of FIG. 7, each contactor 30 ₃ extendssubstantially in the vertical direction formed of an intermediateportion which is connected to the contact substrate 20, a contactportion which is preferably sharpened at the lower end of FIG. 5, and afirst spring portion between the intermediate portion and the contactportion to function as a contact spring, a base portion having a contactpoint which is sharpened at the top end and a second spring portionbetween the base portion and the intermediate portion to function as acontact spring.

[0081] Each of the contactors 30 of FIGS. 5-7 produces contact pressureby a resilient spring force derived from spring portions, i.e., thehorizontal curved portion such as the meander shaped, zig-zag shaped orcurved portion of the contactor, when the contact structure is pressedagainst contact pads 320 on a semiconductor wafer or printed circuitboard 300. The contact pressure also creates a scrubbing effect at thetip of the contactor (contact point) against the surface of contact pad320. In the examples of FIGS. 5 and 7, such a scrubbing effect is alsoachieved at the tip of the base portion (top end of the drawings) on asurface to be connected. Such a scrubbing effect promotes an improvedcontact performance when the contact point scrubs the oxide surface ofthe contact pad 320 to electrically contact the conductive material ofthe contact pad 320 under the oxide surface.

[0082] It should be noted that, the contactors 30 ₁, 30 ₂ and 30 ₃ canbe interchangeably used and produced in accordance with the presentinvention, although the contact structure and its production method willbe described with respect to only one or two of the contactors. Further,various other types of contactors of the present invention will also bedescribed later with reference to FIGS. 9-10, although the detaileddescription will be made only on limited types of contactors. Since thecontactors of the present invention shown in FIGS. 5-7 and 9-10 arevertically mounted, rather than an inclined fashion, on the horizontalsurface of the contact substrate, a large number of contactors can bemounted in the limited space on the contact substrate.

[0083] FIGS. 8A-8B show basic ideas of the present invention forproducing such contactors. In the present invention, as shown in FIG.8A, contactors 30 are produced on a planar surface of a substrate 40which is a silicon substrate or other dielectric substrate in ahorizontal direction, i.e., in a two dimensional manner. Then, thecontactors 30 are removed from the substrate 40 to be mounted on thecontact substrate 20 of FIGS. 5-7 such as a printed circuit board, ICchip, or other contact mechanism in a vertical direction, i.e., in athree dimensional manner.

[0084] In the example of FIG. 8, the contactors 30 are produced on aplanar surface of a silicon or other dielectric substrate 40 in ahorizontal direction. Then, the contactors 30 are transferred from thesubstrate 40 to an adhesive member 90, such as an adhesive tape,adhesive film or adhesive plate (collectively “adhesive tape” or“intermediate plate”). The contactors 30 on the adhesive tape areremoved to be mounted on the contact substrate 20 of FIGS. 5-7 such as aprinted circuit board, IC chip, or other contact mechanism in a verticaldirection, i.e., in a three dimensional manner with use of a pick andplace mechanism.

[0085] FIGS. 9A-9F are examples of various shape of the contactors ofthe present invention to be mounted on the contact substrate in themanner shown in FIGS. 5-7. Each of the examples of FIGS. 9A-9C has apyramidal shape at an end of the base portion (top of FIGS. 9A-9 c)which will be projected from the upper surface of the contact substrate20 of FIGS. 5-7 and a contact tip at the other end (bottom of FIGS. 9A-9c). The contact tips of FIGS. 9A-9E have various shapes to contact withthe surface of the contact target with low contact resistance.

[0086] Each of the examples of FIGS. 9D-9F has a curved thin end at thebase portion (top of FIGS. 9D-9F) which will be projected from the uppersurface of the contact substrate 20 of FIGS. 5-7. Similar to theexamples of FIGS. 9A-9C, the contact tips of FIGS. 9D-9F have variousshapes to contact with the surface of the contact target with lowcontact resistance. Since the contactors have the spring on the baseportion, in forming a probe assembly, a conductive elastomer isunnecessary to produce a spring force or elasticity in the verticaldirection as will be described with reference to FIG. 15.

[0087]FIGS. 10A and 10B show a specific example of contactor of thepresent invention wherein FIG. 10A is a front view and FIG. 10B is aside view thereof. The contactor of FIG. 10 has a base portion whichcontacts a probe card such as shown in FIG. 15 and a spring portionhaving a zig-zag shape in an intermediate position, and a contactportion at a lower end having a contact point to contact the surface ofthe contact target. The base portion and the spring portion will beprotruded from the upper surface of the contact substrate 20 of FIGS.5-7 when mounted thereon. In this example, the contact portion has asubstantially straight shape without a spring.

[0088] In the front view of FIG. 10A, the contact portion has a flangeat its top adjacent to the bottom of the spring portion base portionwhich functions as a stopper when the contactor is inserted in a throughhole of the contact substrate. In the side view of FIG. 10B, the springportion is sized thinner than the contact portion or the base portion tobe easily deformed, thereby exerting the spring force when the contactportion is pressed against the contact target. Because of the twodifferent thickness, i.e, the thinner area for the spring portion andthe thicker area for the contact and base portions, conductive materialsare deposited two or more times to form tow layers or more in theproduction process of the contactor. The example of size in thecontactor of FIG. 10 is: a=760 μm, b=820 μm, c=50 μm, d=200 μm, e=1200μm, f=50 μm, g=20 μm, and h=50 μm.

[0089] FIGS. 11A-11L are schematic diagrams showing an example ofproduction process for producing the contactor 30 (such as contactor 30₃ of FIG. 7) of the present invention. In FIG. 11A, a sacrificial layer42 is formed on a substrate 40 which is typically a silicon substrate.Other dielectric substrate is also feasible such as a glass substrateand a ceramic substrate. The sacrificial layer 42 is made, for example,of silicon dioxide (SiO₂) through a deposition process such as achemical vapor deposition (CVD) The sacrificial layer 42 is to separatecontactors 30 from the silicon substrate in the later stage of theproduction process.

[0090] An adhesion promoter layer 44 is formed on the sacrificial layer42 as shown in FIG. 11B through, for example, an evaporation process. Anexample of material for the adhesion promoter layer 44 includes chromium(Cr) and titanium (Ti) with a thickness of about 200-1,000 angstrom, forexample. The adhesion promoter layer 44 is to facilitate the adhesion ofconductive layer 46 of FIG. 11C on the silicon substrate 40. Theconductive layer 46 is made, for example, of copper (Cu) or nickel (Ni),with a thickness of about 1,000-5,000 angstrom, for example. Theconductive layer 46 is to establish electrical conductivity for anelectroplating process in the later stage.

[0091] In the next process, a photoresist layer 48 is formed on theconductive layer 46 over which a photo mask 50 is precisely aligned tobe exposed with ultraviolet (UV) light as shown in FIG. 11D. The photomask 50 shows a two dimensional image of the contactor 30 which will bedeveloped on the photoresist layer 48. As is well known in the art,positive as well as negative photoresist can be used for this purpose.If a positive acting resist is used, the photoresist covered by theopaque portions of the mask 50 hardens (cure) after the exposure.Examples of photoresist material include Novolak(M-Cresol-formaldehyde), PMMA (Poly Methyl Methacrylate), SU-8 and photosensitive polyimide. In the development process, the exposed part of theresist can be dissolved and washed away, leaving a photoresist layer 48of FIG. 11E having an opening or pattern “A”. Thus, the top view of FIG.11F shows the pattern or opening “A” on the photoresist layer 48 havingthe image (shape) of the contactor 30 ₃.

[0092] In the photolithography process in the foregoing, instead of theUV light, it is also possible to expose the photoresist layer 48 with anelectron beam or X-rays as is known in the art. Further, it is alsopossible to directly write the image of the contact structure on thephotoresist layer 48 by exposing the photoresist 48 with a direct writeelectron beam, X-ray or light source (laser).

[0093] The conductive material such as copper (Cu), nickel (Ni),aluminum (Al), rhodium (Rh), palladium (Pd), tungsten (W) or othermetal, nickel-cobalt (NiCo) or other alloy combinations thereof isdeposited (electroplated) in the pattern “A” of the photoresist layer 48to form the contactor 30 as shown in FIG. 11G. Preferably, a contactmaterial which is different from that of the conductive layer 46 shouldbe used to differentiate etching characteristics from one another aswill be described later. The over plated portion of the contactor 30 inFIG. 11G is removed in the grinding (planarizing) process of FIG. 11H.

[0094] The above noted process is repeated for producing the contactorsuch as shown in FIGS. 10A-10B having different thickness by forming twoor more conductive layers. Namely, after forming a first layer of thecontactors (conductive material), if necessary, the processes of FIGS.11D-11H are repeated to form a second layer or further layer on thefirst layer of the contactors.

[0095] In the next process, the photoresist layer 48 is removed in aresist stripping process as shown in FIG. 11I. Typically, the resistlayer 48 is removed by wet chemical processing. Other examples ofstripping are acetone-based stripping and plasma O₂ stripping. In FIG.11J, the sacrificial layer 42 is etched away so that the contactor 30 isseparated from the silicon substrate 40. Another etching process isconducted so that the adhesion promoter layer 44 and the conductivelayer 46 are removed from the contactor 30 as shown in FIG. 11K.

[0096] The etching condition can be selected to etch the layers 44 and46 but not to etch the contactor 30. In other words, to etch theconductive layer 46 without etching the contactor 30, as noted above,the conductive material used for the contactor 30 must be different fromthe material of the conductive layer 46. Finally, the contactor 30 isseparated from any other materials as shown in the perspective view ofFIG. 11L. Although the production process in FIGS. 11A-11L shows onlyone contactor 30, in an actual production process, as shown in FIGS. 8Aand 8B, a large number of contactors are produced at the same time.

[0097] FIGS. 12A-12D are schematic diagrams showing an example ofproduction process for producing the contactors of the presentinvention. In the this example, an adhesive tape (intermediate plate) 90is incorporated in the production process to transfer the contactors 30from the silicon substrate 40 to the adhesive tape. FIGS. 12A-12D onlyshow the latter part of the production process in which the adhesivetape 90 is involved.

[0098]FIG. 12A shows a process which is equivalent to the process shownin FIG. 11I where the photoresist layer 48 is removed in the resiststripping process. Then, also in the process of FIG. 12A, an adhesivetape (intermediate plate) 90 is placed on an upper surface of thecontactor 30 so that the contactor 30 adheres to the adhesive tape 90.As noted above with reference to FIG. 8B, within the context of thepresent invention, the adhesive tape (intermediate plate) 90 includesother types of adhesive member, such as an adhesive film and adhesiveplate, and the like. The adhesive tape 90 also includes any member whichattracts the contactor 30 such as a magnetic plate or tape, anelectrically charged plate or tape, and the like.

[0099] In the process shown in FIG. 12B, the sacrificial layer 42 isetched away so that the contactor 30 on the adhesive tape 90 isseparated from the silicon substrate 40. Another etching process isconducted so that the adhesion promoter layer 44 and the conductivelayer 46 are removed from the contactor 30 as shown in FIG. 12C.

[0100] As noted above, in order to etch the conductive layer 46 withoutetching the contactor 30, the conductive material used for the contactor30 must be different from the material of the conductive layer. Althoughthe production process in FIGS. 12A-12C shows only one contactor, in anactual production process, a large number of contactors are produced atthe same time. Thus, a large number of contactors 30 are transferred tothe adhesive tape 90 and separated from the silicon substrate and othermaterials as shown in the top view of FIG. 12D.

[0101] FIGS. 13A-13N are schematic diagrams showing a further example ofproduction process for producing the contactor 30 where the contactorsare transferred to the adhesive tape or intermediate plate. In FIG. 13A,an electroplate seed (conductive) layer 342 is formed on a substrate 340which is typically a silicon or glass substrate. The seed layer 342 ismade, for example, of copper (Cu) or nickel (Ni), with a thickness ofabout 1,000-5,000 angstrom, for example. A chrome-inconel layer 344 isformed on the seed layer 342 as shown in FIG. 13B through, for example,a sputtering process.

[0102] In the next process in FIG. 13C, a conductive substrate 346 isformed on the chrome-inconel layer 344. The conductive substrate 346 ismade, for example, of nickel-cobalt (NiCo) with a thickness of about100-130 μm. After passivating the conductive substrate 346, aphotoresist layer 348 with a thickness of about 100-120 μm is formed onthe conductive substrate 346 in FIG. 13D and a photo mask 350 isprecisely aligned so that the photoresist layer 348 is exposed withultraviolet (UV) light as shown in FIG. 13E. The photo mask 350 shows atwo dimensional image of the contactor 30 which will be developed on thesurface of the photoresist layer 348.

[0103] In the development process, the exposed part of the resist can bedissolved and washed away, leaving a photoresist layer 348 of FIG. 13Fhaving a plating pattern transferred from the photo mask 350 having theimage (shape) of the contactor 30 (such as contactor 303 of FIG. 7). Inthe step of FIG. 13G, contactor material is electroplated in the platingpattern on the photoresist layer 348 with a thickness of about 50-60 μm.An example of the conductive material is nickel-cobalt (NiCo). Thenickel-cobalt contactor material will not strongly adhere to theconductive substrate 346 made of nickel-cobalt.

[0104] The above noted process may be repeated for producing thecontactors such as shown in FIGS. 10A-10B having different thickness byforming two or more conductive layers. Namely, after forming a firstlayer of the contactors, if necessary, the processes of FIGS. 13D-13Gare repeated to form a second layer or further layer on the first layerof the contactors.

[0105] In the next process, the photoresist layer 348 is removed in aresist stripping process as shown in FIG. 13H. In FIG. 13I, theconductive substrate 346 is peeled from the chrome-inconel layer 344 onthe substrate 340. The conductive substrate 346 is a thin substrate onwhich the contactors 30 are mounted with a relatively weak adhesivestrength. The top view of the conductive substrate 346 having thecontactors 30 is shown in FIG. 13J.

[0106]FIG. 13K shows a process in which an adhesive tape (intermediateplate) 90 is placed on an upper surface of the contactors 30. Theadhesive strength between the adhesive tape 90 and the contactors 30 isgreater than that between the contactors 30 and the conductive substrate346. Thus, when the adhesive tape 90 is removed from the conductivesubstrate 346, the contactors 30 are transferred from the conductivesubstrate 346 to the adhesive tape 90 as shown in FIG. 13L. FIG. 13Mshows a top view of the adhesive tape 90 having the contactors 30thereon and FIG. 13N is a cross sectional view of the adhesive tape 90having the contactors 30 thereon.

[0107]FIGS. 14A and 14B are schematic diagrams showing an example ofprocess for picking the contactors 30 from the adhesive tape(intermediate plate) 90 and placing the contactors on the contactsubstrate 20. The pick and place mechanism of FIGS. 14A and 14B isadvantageously applied to the contactors produced by the productionprocess of the present invention described with reference to FIGS.12A-12D and FIGS. 13A-13N involving the adhesive tape. FIG. 14A is afront view of the pick and place mechanism 80 showing the first halfprocess of the pick and place operation. FIG. 14B is a front view of thepick and place mechanism 80 showing the second half process of the pickand place operation.

[0108] In this example, the pick and place mechanism 80 is comprised ofa transfer mechanism 84 to pick and place the contactors 30, mobile arms86 and 87 to allow movements of the transfer mechanism 84 in X, Y and Zdirections, tables 81 and 82 whose positions are adjustable in X, Y andZ directions, and a monitor camera 78 having, for example, a CCD imagesensor therein. The transfer mechanism 84 includes a suction arm 85 thatperforms suction (pick operation) and suction release (place operation)operations for the contactors 30. The suction force is created, forexample, by a negative pressure such as vacuum. The suction arm 85rotates in a predetermined angle such as 90 degrees.

[0109] In operation, the adhesive tape 90 having the contactors 30 andthe contact substrate 20 having the bonding locations 32 (or throughholes) are positioned on the respective tables 81 and 82 on the pick andplace mechanism 80. As shown in FIG. 14A, the transfer mechanism 80picks the contactor 30 from the adhesive tape 90 by suction force of thesuction arm 85. After picking the contactor 30, the suction arm 85rotates by 90 degrees, for example, as shown in FIG. 14B. Thus, theorientation of the contactor 30 is changed from the horizontal directionto the vertical direction. This orientation change mechanism is just anexample, and a person skilled in the art knows that there are many otherways to change the orientation of the contactors. The transfer mechanism80 then places the contactor 30 on the bonding location 32 (or throughholes) on the substrate 20. The contactor 30 is attached to the contactsubstrate 20 by being bonded to the surface or inserted in the throughholes.

[0110]FIG. 15 is a cross sectional view showing an example of totalstack-up structure for forming a probe contact assembly using thecontact structure of the present invention. The probe contact assemblyis used as an interface between the device under test (DUT) and the testhead such as shown in FIG. 2. In this example, the probe contactassembly includes a routing board (probe card) 260, and a pogo-pin block(frog ring) 130 provided over the contact structure in the order shownin FIG. 15.

[0111] The contact structure is configured by a plurality of contactors30 ₁ mounted on the contact substrate 20. A base portion 35 of each ofthe contactors is projected at an upper surface of the contact substrate20. In the present invention, the base portion 35 has a spring having,for example, a curved or zig-zag shape. The contactors 30 ₁ may beslightly loosely inserted in through holes on the contact substrate 20in a manner allowing a small movement in the vertical direction whenpressed against the semiconductor wafer 300 and the probe card 260.

[0112] The probe card 260, pogo-pin block 130 and contact structure aremechanically as well as electronically connected with one another,thereby forming a probe contact assembly. Thus, electrical paths arecreated from the contact point of the contactors 30 ₁ to the test head100 through the cables 124 and performance board 120 (FIG. 2). Thus,when the semiconductor wafer 300 and the probe contact assembly arepressed with each other, electrical communication will be establishedbetween the DUT (contact pads 320 on the wafer 300) and the test system.

[0113] The pogo-pin block (frog ring) 130 is equivalent to the one shownin FIG. 2 having a large number of pogo-pins to interface between theprobe card 260 and the performance board 120. At upper ends of thepogo-pins, cables 124 such as coaxial cables are connected to transmitsignals to printed circuit boards (pin electronics cards) 150 in thetest head 100 in FIG. 2 through the performance board 120. The probecard 260 has a large number of electrodes 262 and 265 on the upper andlower surfaces thereof. When assembled, the base portions 35 of thecontactors 30 contact the electrodes 262. The electrodes 262 and 265 areconnected through interconnect traces 263 to fan-out the pitch of thecontact structure to meet the pitch of the pogo-pins in the pogo-pinblock 130. Because the contactors 30 are loosely inserted in the throughholes of the contact substrate 20, the springs provided on the baseportions of the contactors produce resilient contact force toward theelectrodes 262 as well as the contact pads 320 when pressed against thesemiconductor wafer 300.

[0114]FIG. 16 is a cross sectional view showing another example of probecontact assembly using the contact structure of the present invention.The probe contact assembly is used as an interface between the deviceunder test (DUT) and the test head such as shown in FIG. 2. In thisexample, the probe contact assembly includes a conductive elastomer 250,a probe card 260, and a pogo-pin block (frog ring) 130 provided over thecontact structure. Since the base portion of the contactor 30 has aspring as mentioned above, such a conductive elastomer is basicallyunnecessary. However, such a conductive elastomer is still useful forcompensating the unevenness of the gap between the probe card 260 andthe contact structure.

[0115] The conductive elastomer 250 is provided between the contactstructure and the probe card 260. When assembled, the base portions 35of the contactors 30 contact the conductive elastomer 250. Theconductive elastomer 250 is an elastic sheet having a large number ofconductive wires in a vertical direction. For example, the conductiveelastomer 250 is comprised of a silicon rubber sheet and a multiple rowsof metal filaments. The metal filaments (wires) are provided in thevertical direction of FIG. 16, i.e., orthogonal to the horizontal sheetof the conductive elastomer 250. An example of pitch between the metalfilaments is 0.05 mm or less and thickness of the silicon rubber sheetis about 0.2 mm. Such a conductive elastomer is produced by Shin-EtsuPolymer Co. Ltd, Japan, and available in the market.

[0116]FIG. 17 is a cross sectional view showing a further example ofprobe contact assembly using the contact structure of the presentinvention. In this example, the contact structure is formed of aplurality of contact structure (substrate) blocks. Further, the contactsubstrate block is formed of a plurality of standard substrates stackedtogether. For example, the contact structure of FIG. 20 is configured bytwo contact structure (substrate) blocks 20 ₁ and 20 ₂ each having threestandard silicon substrates 22 ₁, 22 ₂ and 22 ₃.

[0117] Although only one of them is shown, a plurality of contactors 30₁ are attached to each contact substrate 20 in a manner that an end ofeach contactor 30 ₁ is projected from the upper surface of the substrate22. Typically, the contact substrate 22 is made of silicon wafer,however, other dielectric materials such as ceramic, glass, polyimideand the like are also feasible. In the preferred embodiment, the contactsubstrate 22 is a multi-layered substrate having multiple standardsilicon wafers such as three wafers 22 ₁, 22 ₂ and 22 ₃ which arestacked and bonded to one another. The major reason of using themultiple silicon wafers is to attain a sufficient thickness of thecontact substrate without increasing tolerance in mechanical dimensions.Thus, the number of silicon wafers can be selected freely such as one ormore depending on the specific requirements in the design. The standardsilicon wafers have the same thickness but different outer shape tocreate engagement mechanism such as teeth and recesses as shown in FIG.20.

[0118]FIG. 18 is a cross sectional view showing details of contactstructure of the present invention incorporated in the probe contactassembly of FIG. 15. The contactor 30 ₁ having the zig-zag shaped springis attached to the contact substrate 20 in a manner that a straight bodyof the contactor 30 ₁ having a contact tip at its end is inserted in athrough hole 25. In this example, the contact substrate 20 is amulti-layered substrate having three standard silicon wafers 22 ₁, 22 ₂and 22 ₃ which are stacked and fusion bonded to one another. An exampleof thickness of each of the silicon wafers 22 ₁-22 ₃ is about 0.5 mm.The based portion 35 of the contactor 30 ₁ having the spring isprojected from the upper surface of the contact substrate 20. Thecontactor 30 ₁ has a flange like portion 34 to be fitted with a stepprovided in the through hole 25. A contact point at the tip of thecontactor 30 ₁ is preferably sharpened to promote the scrubbing effecton the surface of the contact target.

[0119] The process of forming three layered substrate 20 and throughholes thereon shown in FIG. 18 is briefly explained in the following.First, the second wafer 22 ₂ and the third wafer 22 ₃ are directlybonded through, for example, silicon fusion bonding. Then the wafers 22₂ and 22 ₃ are polished both front and back, and through holes arecreated therethrough by an etching process. Such a deep trench etchingis achieved, for example, by reactive ion etching using a reactive gasplasma. As shown in FIG. 18, the size of the through holes on the secondand third wafers 22 ₂ and 22 ₃ must be smaller than the flange likeportion 34 of the contactor 30 to form the steps in the through holes.

[0120] Then, the first wafer 22 ₁ is polished its front and backsurfaces and through holes 25 are created therethrough by the deeptrench etching noted above. The size of the through holes of the firstwafer 22 ₁ is larger than that of the second and third wafers 22 ₂ and22 ₃ to receive the flange like portion 34 of the contactor 30 as notedabove. The first wafer 22 ₁ is aligned and fusion bonded to the secondand third wafers 22 ₂ and 22 ₃. For insulation, silicon oxide layers of,for example, at least one micrometer is preferably grown on all of theexposed surfaces of the contact substrate produced in this manner.

[0121]FIG. 19 is a perspective view showing an example of contactstructure (substrate) blocks of the present invention each having alarge number of contactors 30 produced through the process shown inFIGS. 8A and 8B. This example shows a plurality of contact structureblocks 20 to be assembled with one another to build a contact structureof desired size and desired number of contactors. In FIG. 19, althougheach contact structure block includes contactors assembled in a singleline, a contact structure block of the present invention may includecontactors aligned in two or more lines, i.e, a matrix manner.

[0122] As noted above, one of the features of the present invention isthe capability of combining a plurality of contact structure blocks 20to create a contact structure (probe contact assembly) of increasedoverall size and number of contactors. In the example of FIG. 19, fourcontact structure blocks 20 are prepared to be connected to one another.Although not shown in the example of FIG. 19, each contact substrate 22has connection or engagement mechanism such as teeth at the outer edgesthereof.

[0123]FIG. 20 is a perspective view of the contact structure formed by aplurality of contact structure blocks of the present invention. In thisexample, five contact substrates are connected with one another tocreate a contact structure having an overall size which is an integermultiple of the size of the contact structure block. For simplicity ofillustration, the contactors are not shown on the contact substrates 22.By combining the contact substrates 22 in this manner, a contactassembly of desired size such as equivalent to the size of a twelve-inchsemiconductor wafer can be established.

[0124] In this example, the right and left edges of the contactsubstrate are provided with engagement teeth 55 and recesses 65. Thesize of the tooth 55 and recess 65 is the same in the right and leftedges, however, the position of the tooth 55 and recess 65 is shifted byone unit. Thus, the left edge of one contact substrate 22 fits with theright edge of the another contact substrate 22. Although not shown inFIG. 20, a projection is provided at a distal end of the contactsubstrate 22 to fit in a groove 70 at a proximal end of another contactsubstrate 22. Instead of using the projections and grooves, it is alsopossible to use the teeth and recesses such as in the right and leftedges described above. The contactors 30 will be mounted on the contactsubstrates 22 in the manner shown in FIGS. 19 in through holes 25.

[0125] According to the present invention, the contact structure has avery high frequency bandwidth to meet the test requirements of nextgeneration semiconductor technology. Since the large number ofcontactors are produced at the same time on the substrate withoutinvolving manual handling, it is possible to achieve consistent quality,high reliability and long life in the contact performance. Further,because the contactors are assembled on the same substrate material asthat of the device under test, it is possible to compensate positionalerrors caused by temperature changes. Further, it is possible to producea large number of contactors in a horizontal direction on the siliconsubstrate by using relatively simple technique. The contact structureproduced by the present invention is low cost and high efficiency andhas high mechanical strength and reliability. The contact structureproduced by the method of the present invention are advantageouslyapplied in testing a semiconductor wafer, packaged LSI, multi-chipmodule and the like including burn-in testing.

[0126] Although only a preferred embodiment is specifically illustratedand described herein, it will be appreciated that many modifications andvariations of the present invention are possible in light of the aboveteachings and within the purview of the appended claims withoutdeparting the spirit and intended scope of the invention.

What is claimed is:
 1. A contact structure for establishing electricalconnection with contact targets, comprising: a contact substrate havingthrough holes running through upper and lower surfaces; and a pluralityof contactors made of conductive material and mounted vertically on ahorizontal surface of the contact substrate where each of the contactorshas a substantially straight shape and is comprised of a contact portionwhich is protruded in a vertical direction to form a contact point, anintermediate portion which is inserted in the through hole provided onthe contact substrate, and a base portion having a base end whichfunctions as a contact pad and a spring portion provided between thebase end and the intermediate portion; wherein the spring portion has acurved, inclined, meander or zig-zag shape to exert the resilientcontact force when the contactor is pressed against the contact target,and an end of the base portion is projected from the surface of thecontact substrate and functions as a contact point for electricalconnection with an external component, and an end of the contact portioncontacts the contact target when the contact structure is pressedagainst the contact targets.
 2. A contact structure for establishingelectrical connection with contact targets as defined in claim 1,wherein the contact substrate is formed of a single or a plurality ofdielectric substrates bonded to one another and the through holes on thecontact substrate are created through an etching process.
 3. A contactstructure for establishing electrical connection with contact targets asdefined in claim 1, wherein each of the contactors is provided with aflange like shape at the intermediate portion thereof to be fitted inthe through holes on the contact substrate.
 4. A contact structure forestablishing electrical connection with contact targets as defined inclaim 1, wherein the contact substrate is formed of first and secondsemiconductor wafers which are bonded together on which through holesare produced for mounting the contactors therethrough.
 5. A contactstructure for establishing electrical connection with contact targets asdefined in claim 1, wherein the contact substrate is formed of threelayers of semiconductor wafers which are bonded together on whichthrough holes are produced for mounting the contactors therethrough. 6.A contact structure for establishing electrical connection with contacttargets as defined in claim 1, wherein the contactors are produced on aplanar surface of a flat substrate in a horizontal direction and removedfrom the flat substrate and mounted on the contact substrate in avertical direction.
 7. A contact structure for establishing electricalconnection with contact targets as defined in claim 1, wherein thecontact substrate has an engagement mechanism at outer edges thereof forconnecting other contact substrates at the outer edges to create acontactor assembly of arbitrary size and number of contactors.
 8. Acontact structure for establishing electrical connection with contacttargets as defined in claim 7, wherein the engagement mechanism includesteeth and recesses provided at outer edges of the contact substrate insuch a way that the engagement teeth and recesses in one edge fit withthe engagement teeth and recesses in an opposite edge of other contactsubstrate, thereby assembling a plurality of contact substrates toestablish the contactor assembly of desired size, shape and number ofcontactors.
 9. A contact structure for establishing electricalconnection with contact targets as defined in claim 1, wherein thecontact substrate is made of silicon.
 10. A contact structure forestablishing electrical connection with contact targets as defined inclaim 1, wherein the contact substrate is made of dielectric materialincluding polyimide, ceramic or glass.
 11. A method for producing acontact structure, comprising the following steps of: (a) forming asacrificial layer on a surface of a silicon substrate; (b) forming aphotoresist layer on the sacrificial layer; (c) aligning a photo maskover the photoresist layer and exposing the photoresist layer withultraviolet light through the photo mask, the photo mask including animage of the contactors each having a spring portion between a baseportion and an intermediate portion; (d) developing patterns of theimage of the contactors on a surface of the photoresist layer; (e)forming the contactors made of conductive material in the patterns onthe photoresist layer by depositing the conductive material; (f)stripping the photoresist layer off; (g) removing the sacrificial layerby an etching process so that the contactors are separated from thesilicon substrate; and (h) mounting the contactors on a contactsubstrate having through holes to receive ends of the contactors thereinso that at least one end of each of the contactors functions as acontact pad for electric connection.
 12. A method for producing acontact structure, comprising the following steps of: (a) forming asacrificial layer on a surface of a substrate; (b) forming a photoresistlayer on the sacrificial layer on the substrate; (c) aligning a photomask over the photoresist layer and exposing the photoresist layer withultraviolet light through the photo mask, the photo mask including animage of the contactors each having a spring portion between a baseportion and an intermediate portion; (d) developing patterns of theimage of the contactors on a surface of the photoresist layer; (e)forming the a first layer of contactors made of electric conductivematerial in the patterns on the photoresist layer by an electroplatingprocess; (f) stripping the photoresist layer off; (g) placing anadhesive tape on the contactors so that upper surfaces of the contactorsare attached to the adhesive tape; (h) removing the sacrificial layer byan etching process so that the contactors on the adhesive tape areseparated from the silicon substrate; and (i) mounting the contactors ona contact substrate having through holes to receive therein ends of thecontactors wherein at least one end of each of the contactors functionas a pad for electric connection.
 13. A method for producing a contactstructure, comprising the following steps of: (a) forming an conductivesubstrate made of electric conductive material on a dielectricsubstrate; (b) forming a photoresist layer on the conductive substrate;(c) aligning a photo mask over the photoresist layer and exposing thephotoresist layer with ultraviolet light through the photo mask, thephoto mask including an image of the contactors each having a springportion between a base portion and an intermediate portion; (d)developing patterns of the image of the contactors on a surface of thephotoresist layer; (e) forming a first layer of contactors made ofelectric conductive material in the patterns on the photoresist layer byan electroplating process; (f) stripping off the photoresist layer; (g)placing an adhesive tape on the contactors on the conductive substrateso that upper surfaces of the contactors adhere to the adhesive tapewherein adhesive strength between the contactor and the adhesive tape islarger than that between the contactor and the conductive substrate; (h)peeling the conductive substrate so that the contactors on the adhesivetape are separated from the conductive substrate; and (i) mounting thecontactor on a contact substrate having a through hole in such a way thean end of the contactor is projected from an opposite surface of thecontact substrate.
 14. A probe contact assembly for establishingelectrical connection with contact targets, comprising: a contactsubstrate having a plurality of contactors mounted on a surface thereof;a probe card for mounting the contact substrate and establishingelectrical communication between the contactors and electrodes providedon the probe card; and a pin block having a plurality of contact pins tointerface between the probe card and a semiconductor test system whenthe pin block is attached to the probe card; wherein the contactors aremounted vertically on a horizontal surface of the contact surface whereeach of the contactors has a substantially straight shape and iscomprised of a contact portion which is protruded in a verticaldirection to form a contact point, an intermediate portion which isinserted in the through hole provided on the contact substrate, and abase portion having a base end which functions as a contact pad and aspring portion provided between the base end and the intermediateportion; and wherein the spring portion has a curved, inclined, meanderor zig-zag shape to exert the resilient contact force when the contactoris pressed against the contact target, and an end of the base portion isprojected from the surface of the contact substrate and functions as acontact point for electrical connection with an external component. 15.A probe contact assembly for establishing electrical connection withcontact targets as defined in claim 14, wherein the contact substrate isformed of a single or a plurality of semiconductor wafers bonded to oneanother and the through holes on the contact substrate are createdthrough an etching process.
 16. A probe contact assembly forestablishing electrical connection with contact targets as defined inclaim 14, wherein each of the contactors is provided with a flange likeshape at the intermediate portion thereof to be fitted in the throughholes on the contact substrate.
 17. A probe contact assembly forestablishing electrical connection with contact targets as defined inclaim 14, wherein the contact substrate is formed of three layers ofsemiconductor wafers which are bonded together on which through holesare produced for mounting the contactors therethrough.
 18. A probecontact assembly for establishing electrical connection with contacttargets as defined in claim 14, wherein the contactors are produced on aplanar surface of a flat substrate in a horizontal direction and removedfrom the flat substrate and mounted on the contact substrate in avertical direction.
 19. A probe contact assembly for establishingelectrical connection with contact targets as defined in claim 14,wherein the contact substrate has an engagement mechanism at outer edgesthereof for connecting other contact substrates at any desired edges tocreate a contactor assembly of arbitrary size.
 20. A probe contactassembly for establishing electrical connection with contact targets asdefined in claim 14, wherein the engagement mechanism includes teeth andrecesses provided at outer edges of the contact substrate in such a waythat the engagement teeth and recesses in one edge fit with theengagement teeth and recesses in an opposite edge of other contactsubstrate, thereby assembling a plurality of contact substrates toestablish the contactor assembly of desired size, shape and number ofcontactors.